1. Field of the Invention
The present invention relates to a belt grinder attachment for powered rotary tools and in particular to a belt grinder attachment in which the grinding belt traverses a path normal to the axis of the tool for improved control of belt positioning on the work piece.
2. Description of the Prior Art
There is a very popular concept powered rotary tool manufactured by a number of companies and marketed under a variety of tradenames. Each tool has an electric motor mounted in a handle and adapted to drive a chuck on a free end of the tool. The chuck is adapted to receive a wide variety of rotary tool accessories, such as drill bits, saw blades, sanding discs and drums and similar rotary operating devices. These tools are widely used by both hobbyist and the professional craftsman for tool and model making and similar detailed work.
Theretofor these tools have generally been restricted to using only disc and drum grinding and sending devices as no suitable belt grinder attachments have been available. Some of the problems of the prior art belt grinder devices included difficulty of attachment to the basic tool, including propritary attachment to only the tools of the belt grinder manufacturer. Further problems were the attachment had the belt running generally along the axis of the tool making positioning of the belt against the work piece difficult in many instances. An example of this type of in-line tool attachment can be found in U.S. Pat. No. 3,496,679. Another example of a belt grinder attachment can be found in U.S. Pat. No. 2,301,853. However, this attachment presents a number of different problems. This patent shows a tool which is mounted in a handle and the belt grinder attachment is mounted parallel to the handle, normal to the axis of the tool, the handle, tool and attachment forming a generally U-shape. This arrangement creates a parallax problem for the worker in trying to control the belt. It is necessary to have guide means provided on this assembly to both support and correctly position the belt with respect to the work piece.
Examples of belt grinder attachments for hand drills can be found in U.S. Pat. Nos. 2,976,652 and 3,566,549. Examples of minature belt grinding devices may be found in U.S. Pat. Nos. 3,427,757; 3,510,988; 3,619,949; and 3,643,385. None of the devices shown in the latter group of patents could be readily adapted as an attachment for an existing powered rotary tool.
The present invention overcomes many of the above discussed problems of the prior art.